Massachusetts Democrats, especially President Barack Obama’s friend and ally Deval Patrick, are poised to play a key role in the battle with likely Republican nominee Mitt Romney.

They’ve been at it for awhile, revelling in the chance to needle Romney for his role in the Massachusetts health care reform.

But suddenly, the campaign has changed, forcing an abrupt shift in the way they’re using that reform as an anti-Romney weapon.

Beneath the watchful eyes of past statesmen, Gov. Patrick and others threw a birthday party Wednesday for the state healthcare reform, with a shoutout to architects who weren’t there, like late Sen. Ted Kennedy and former Gov. Mitt Romney.

“Today is about celebrating a really great success,” said Gov. Patrick at the rally.

In the six years since Romney signed the reform into law here, critics from Gov. Patrick to President Obama have rarely passed up a chance to praise his role in it, knowing that conservative antipathy for the bill might derail Romney’s presidential run.

But now that Romney has the nomination in the bag, and the Supreme Court may be poised to throw out the federal health reform law, praise for Romney’s performance seems noticeably more grudging.

“I think a lot of the leadership in bringing the parties together came from the Senate president, (Robert) Travaglini,” said Gov. Patrick.

“Romney had the political skills and sense to realize there was a potential victory here. And at the time, he was looking for victories,” said Travaglini, the former Senate president. “If there was any real leader in any of this, I would give that credit to Ted Kennedy, not Mitt Romney.”

So let’s get this straight. When health care reform was seen as a Romney liability, no praise was too lavish.

But now that the campaign is about persuading moderate swing voters who might be looking for a successful consensus builder, Romney was apparently more of a supporting actor to Ted Kennedy.

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